You cannot undo line 10000 because inventory pick lines have already been posted

Microsoft Dynamics NAV 2009 R2

Version US Dynamics NAV 6.0 SP1 (6.00.33046)

My location is setup as Require Pick = True.  We use Inventory Pick functionality (not Warehouse Shipment, Directed Put-away and Picks).  I’ve discovered that I can’t undo a shipment after the Pick has been posted.  When I attempt to undo the Posted Shipment, I receive the message “You cannot undo line 10000 because inventory pick lines have already been posted”.

I see that code in codeunit 5817, Undo Posting Management, has a function that results in that message (TestPostedInvtPickLine).  I could change that behavior.  But is there any reason I shouldn’t want to do that?